tracing: Fix selftest config check for function graph start up test

There's a new test in trace_selftest_startup_function_graph() that
requires the use of ftrace args being supported as well does some tricks
with dynamic tracing. Although this code checks HAVE_DYNAMIC_FTRACE_WITH_ARGS
it fails to check DYNAMIC_FTRACE, and the kernel fails to build due to
that dependency.

Also only define the prototype of trace_direct_tramp() if it is used.

Link: https://lkml.kernel.org/r/20211021134357.7f48e173@gandalf.local.homeAcked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_selftest.c

@@ -784,7 +784,11 @@ static struct fgraph_ops fgraph_ops __initdata  = {
 	.retfunc		= &trace_graph_return,
 };
 
+#if defined(CONFIG_DYNAMIC_FTRACE) && \
+    defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)
+#define TEST_DIRECT_TRAMP
 noinline __noclone static void trace_direct_tramp(void) { }
+#endif
 
 /*
  * Pretty much the same than for the function tracer from which the selftest
@@ -845,7 +849,7 @@ trace_selftest_startup_function_graph(struct tracer *trace,
 		goto out;
 	}
 
-#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+#ifdef TEST_DIRECT_TRAMP
 	tracing_reset_online_cpus(&tr->array_buffer);
 	set_graph_array(tr);